You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
You are given a sentence and a question in the input. The information provided in the sentence should be enough to answer the question. You're expected to write the correct answer. Do not use any facts other than those provided in the sentence.

Sentence: GOP leaders submitted the new offer Tuesday afternoon in an effort to appease Democrats, whose votes are needed to avert a shutdown of federal agencies, several House and Senate aides said. Question: Who has to be appeased to keep the government open?
Solution: Democrats.
Why? The sentence says that "Democrats" have to be appeased, which answers the question.

New input: Sentence: The beaver thanked both the bear and the wolf for trying out his new bridge and then started to build yet another bridge close to the first bridge. 
Question: what did the bear and wolf cross, and why did they turn back?
Solution:
They crossed a bridge, and they turned back because they were merely testing the structural integrity of the bridge.